KR20110093936A - Control device for hybrid construction machine - Google Patents

Abstract

It is a control apparatus of a hybrid construction machine, and is provided with the regulator which controls so that the tilting angle of a variable displacement pump may become large, so that the pilot pressure which acts is low, and if a controller determines that all the operation valves are in neutral positions, The main switching valve is switched so that the discharge oil of the type pump is guided to the regenerative hydraulic motor, and the pilot selection valve is switched so that the second pilot flow path in which the electromagnetic variable pressure reducing valve is installed is in communication with the regulator.

Description

CONTROL DEVICE FOR HYBRID CONSTRUCTION MACHINE}

TECHNICAL FIELD This invention relates to the control apparatus of the hybrid construction machine which uses an electric motor as a drive source.

The hybrid structure in a construction machine, such as a power shovel, generates electric power by rotating a generator at the surplus output of an engine, for example, stores the electric power in a battery, and drives an electric motor with the electric power of the battery to operate an actuator. It is supposed to be. In addition, the generator generates power by rotating the generator with the discharged energy of the actuator. Similarly, the power is stored in the battery, and the electric motor is driven by the power of the battery to operate the actuator (see JP2002-275945A).

Moreover, in a power shovel etc., even when an actuator is stopped, the engine keeps rotating. At this time, the pump also rotates together with the engine, so that the pump discharges a so-called standby flow rate.

In the conventional hybrid structure described above, the standby flow rate discharged from the pump when the actuator is stopped is only returned to the tank and has not been effectively used.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a control device for a hybrid construction machine that effectively utilizes a standby flow rate of a pump to exert a power generation function to achieve energy regeneration.

This invention is a control apparatus of a hybrid construction machine, Comprising: When a variable displacement pump, the several operation valve which controls the flow volume of the hydraulic fluid guide | induced to each actuator from the said variable displacement pump, and when the said operation valve is a neutral position, A neutral flow path for guiding discharge oil of the variable displacement pump to a tank, a pilot pressure generation throttle portion provided downstream of the operation valve in the neutral flow path, and an upstream side of the pilot pressure generation throttle portion; A first pilot flow path through which the generated pressure is induced, a regulator controlling the tilting angle of the variable displacement pump to increase as the pilot pressure acting is lowered, an operation condition detector for detecting an operation condition of the operation valve, and Regenerative hydraulic motor rotated by the discharge oil of the variable displacement pump, a generator connected to the hydraulic motor, and the variable displacement type A main switching valve for selectively guiding hydraulic oil discharged from the pump to the operation valve or the hydraulic motor, a second pilot flow passage for guiding pilot pressure oil supplied from a pilot pressure source to the regulator, and the first pilot flow passage or the first pilot flow passage. A pilot selection valve for selectively communicating two pilot flow paths with said regulator, an electromagnetic variable pressure reducing valve provided in said second pilot flow path and capable of variably controlling a pilot pressure induced from said pilot pressure source and acting on said regulator, and said operation On the basis of the detection result of the condition detector, when it is determined that all of the operation valves are in the neutral position, the second pilot flow path is switched while switching the main switching valve so that discharge oil of the variable displacement pump is led to the hydraulic motor. To communicate with the regulator And a controller for switching the pilot selection valve.

According to the present invention, when it is determined that all the operation valves are in the neutral position, the discharge oil of the variable displacement pump is guided to the regenerative hydraulic motor, so that the standby flow rate of the variable displacement pump can be effectively used. In addition, since the pressure acting on the regulator is variably controlled by the electromagnetic variable pressure reducing valve, the tilting angle of the variable displacement pump can be freely controlled as necessary. Thus, there is no tendency to run out of energy for charging the battery.

1 is a circuit diagram of a control device for a hybrid construction machine according to an embodiment of the present invention.
2A and 2B are flowcharts showing control procedures executed by the controller.

EMBODIMENT OF THE INVENTION Hereinafter, the control apparatus of the hybrid construction machine which concerns on embodiment of this invention is demonstrated with reference to drawings. In the following embodiment, the case where a hybrid construction machine is a power shovel is demonstrated.

As shown in FIG. 1, the power shovel is provided with the 1st main pump 71 and the 2nd main pump 72 of the variable displacement type which rotate by the drive force of the engine 73 as a prime mover. The first main pump 71 and the second main pump 72 rotate coaxially. The engine 73 is provided with a generator 1 that exerts a power generation function by utilizing the power of the engine 73. In addition, the engine 73 is provided with a rotation speed sensor 74 as a rotation speed detector for detecting the rotation speed of the engine 73.

The hydraulic oil discharged from the first main pump 71 is supplied to the first circuit system. The first circuit system sequentially includes an operation valve 2 for controlling the swing motor from the upstream side, an operation valve 3 for controlling the arm cylinder, an operation valve 4 for boom 2 speed for controlling the boom cylinder, It has the operation valve 5 which controls a spare attachment, and the operation valve 6 which controls the 1st motor for driving for a left run. Each operation valve 2-6 controls the flow volume of the hydraulic fluid guide | induced to each actuator from the 1st main pump 71, and controls the operation | movement of each actuator.

The first main flow path 75 through which the discharged hydraulic oil is guided is connected to the first main pump 71. The first main flow passage 75 branches into the neutral flow passage 7 and the parallel flow passage 8. Each operation valve 2-6 is connected via the neutral flow path 7 and the parallel flow path 8. In the first main flow path 75, the first main switching valve 15 for selectively inducing the hydraulic oil discharged from the first main pump 71 to the operation valves 2 to 6 or the regenerative hydraulic motor 88 described later. ) Is installed.

On the downstream side of the operation valves 2 to 6 in the neutral flow passage 7, a throttle 9 for generating a pilot pressure is provided. The throttle part 9 produces | generates a high pilot pressure upstream when there are many flow rates which pass, and produces a low pilot pressure on an upstream side when there is little flow volume which passes.

The neutral flow path 7 passes all or part of the hydraulic oil discharged from the first main pump 71 through the throttle 9 when all the operation valves 2 to 6 are in the neutral position or the neutral position vicinity. Guide to the tank 94. At this time, the flow rate passing through the throttle 9 increases, so that a high pilot pressure is generated.

On the other hand, when the operation valves 2 to 6 are switched to the state of the full stroke, the neutral flow path 7 is closed and the flow of fluid is lost. In this case, the flow rate passing through the throttle 9 is almost eliminated, and the pilot pressure is kept at zero. However, depending on the operation amount of the operation valves 2 to 6, a part of the hydraulic oil discharged from the first main pump 71 is guided to the actuator, and the rest is guided to the tank 94 from the neutral flow path 7. , The throttle 9 generates a pilot pressure according to the flow rate of the working oil of the neutral flow path (7). That is, the throttle part 9 produces | generates the pilot pressure according to the operation amount of the operation valves 2-6.

The 1st pilot flow path 10a is branched and connected between the operation valve 6 of the lowest downstream in the neutral flow path 7, and the throttle part 9. The pressure of the neutral flow path 7 which arises in the upstream of the throttle part 9 is guide | induced as pilot pressure to the 1st pilot flow path 10a. The first pilot oil passage 10a is connected to a regulator 12 that controls the tilting angle of the first main pump 71. The regulator 12 controls the tilting angle of the first main pump 71 in inverse proportion to the pilot pressure of the first pilot flow path 10a to control the displacement per rotation of the first main pump 71. Therefore, when the operation valves 2 to 6 are full stroke and the flow of the neutral flow path 7 is lost, and the pilot pressure of the first pilot flow path 10a is zero, the tilting angle of the first main pump 71 is maximum. In this case, the displacement per revolution is maximized.

The pilot pump 96 as a pilot pressure source is also provided in the power shovel. Pilot pressure oil supplied from the pilot pump 96 is guided to the regulator 12 via the second pilot flow passage 11. A first pilot selector valve 78 is provided in the first pilot passage 10a and the second pilot passage 11 to selectively communicate one of them with the regulator 12. The solenoid is connected to the controller 90, and the 1st pilot selection valve 78 is switched to a 1st position or a 2nd position based on the output signal of the controller 90. FIG. The 1st pilot selection valve 78 is set to a 1st position (position shown in FIG. 1) in a non-excitation normal state, and is set to a 2nd position in a solenoid state. In the first position, the first pilot flow path 10a is connected to the regulator 12, and the regulator 12 tilts the first main pump 71 based on the pilot pressure derived from the first pilot flow path 10a. To control the angle. On the other hand, in the second position, the second pilot flow passage 11 is connected to the regulator 12, and the regulator 12 is based on the pilot pressure derived from the second pilot flow passage 11 and the first main pump 71. To control the tilt angle.

The second pilot oil passage 11 is provided with an electromagnetic variable pressure reducing valve 77 capable of variably controlling the pilot pressure induced from the pilot pump 96 and acting on the regulator 12. The solenoid of the electromagnetic variable pressure reducing valve 77 is connected to the controller 90, and the secondary pressure, which is the outlet pressure of the electromagnetic variable pressure reducing valve 77, is variably controlled based on the output signal of the controller 90. Therefore, when the tilting angle of the first main pump 71 is controlled based on the pilot pressure of the second pilot flow path 11, the tilting angle can be freely set by controlling the secondary pressure of the electromagnetic variable pressure reducing valve 77. It becomes possible.

The 1st main switching valve 15 is a pilot operation type | mold valve switched to a 1st position (position shown in FIG. 1), and a 2nd position based on the pilot pressure guide | induced to the pilot chamber 15a. The pilot pressure oil supplied from the pilot pump 96 via the 3rd pilot flow path 13 is guide | induced to the pilot chamber 15a.

In the third pilot flow passage 13, a pilot electromagnetic switching valve 14 that is switched to the cutoff position or the communication position based on the output signal of the controller 90 is provided. The solenoid is connected to the controller 90, and the pilot electromagnetic switching valve 14 is switched to a cutoff position or a communication position based on the output signal of the controller 90. The pilot electromagnetic switching valve 14 is set to the shutoff position (position shown in Fig. 1) in the normal state of the non-excited state, and is set to the communication position in the excited state of the solenoid. When the pilot electromagnetic switching valve 14 is in the shutoff position, the supply of pilot pressure oil from the pilot pump 96 to the pilot chamber 15a is cut off, and the first main switching valve 15 is set to the first position in the normal state. . As a result, the hydraulic oil discharged from the first main pump 71 is led to the operation valves 2 to 6. On the other hand, in the communication position of the pilot electromagnetic switching valve 14, the pilot pressure oil is supplied from the pilot pump 96 to the pilot chamber 15a, and the first main switching valve 15 is set to the second position. As a result, the hydraulic oil discharged from the first main pump 71 is guided to the regenerative hydraulic motor 88.

The second main pump 72 is connected to the second circuit system. The second circuit system sequentially operates from the upstream side, the operation valve 16 for controlling the second travel motor for right travel, the operation valve 17 for controlling the bucket cylinder, and the operation valve for controlling the boom cylinder. 18 and an arm double speed operation valve 19 for controlling the arm cylinder. Each operation valve 16-19 controls the flow volume of the hydraulic fluid guide | induced to each actuator from the 2nd main pump 72, and controls the operation | movement of each actuator.

A second main flow path 76 through which discharged hydraulic oil is guided is connected to the second main pump 72. The second main flow passage 76 branches into the neutral flow passage 20 and the parallel flow passage 21. Each operation valve 16-19 is connected through the neutral flow path 20 and the parallel flow path 21. As shown in FIG. In the second main flow path 76, a second main switching valve 26 for selectively inducing hydraulic oil discharged from the second main pump 72 to the operation valves 16 to 19 or the regenerative hydraulic motor 88 is provided. Is installed.

On the downstream side of the operation valves 16 to 19 in the neutral flow path 20, an throttle part 22 for generating a pilot pressure is provided. The throttle part 22 has the same function as the throttle part 9 on the side of the 1st main pump 71.

The 1st pilot flow path 10b is connected between the operation valve 19 of the lowest flow in the neutral flow path 20, and the throttle part 22. As shown in FIG. The pressure of the neutral flow path 20 which arises in the upstream of the throttle part 22 is guide | induced as pilot pressure to the 1st pilot flow path 10b. The first pilot flow path 10b is connected to a regulator 25 that controls the tilting angle of the second main pump 72. The regulator 25 controls the tilt angle of the second main pump 72 in inverse proportion to the pilot pressure of the first pilot flow path 10b to control the displacement per second of the second main pump 72. Therefore, when the operation valves 16-19 are full stroke and the flow of the neutral flow path 20 disappears and the pilot pressure of the 1st pilot flow path 10b becomes zero, the tilting angle of the 2nd main pump 72 will be maximum. In this case, the displacement per revolution is maximized.

The second pilot oil passage 11 branches downstream of the electromagnetic variable pressure reducing valve 77 and is connected to the regulator 25. In the first pilot flow path 10b and the second pilot flow path 11, a second pilot selection valve 79 for selectively communicating with one of the regulators 25 is provided. The solenoid is connected to the controller 90, and the 2nd pilot selection valve 79 is switched to a 1st position (position shown in FIG. 1), or a 2nd position based on the output signal of the controller 90. FIG. The configuration and operation of the second pilot selection valve 79 are the same as the first pilot selection valve 78 on the first main pump 71 side.

Since the first pilot selector valve 78 and the second pilot selector valve 79 are installed in parallel to the second pilot flow path 11 downstream of the electromagnetic variable pressure reducing valve 77, in a state where both are set to the second position, The same pilot pressure controlled by the electromagnetic variable pressure reducing valve 77 is applied to the regulators 12 and 25.

The second main switching valve 26 is a pilot operated valve that is switched to the first position (the position shown in FIG. 1) and the second position based on the pilot pressure guided to the pilot chamber 26a. The third pilot flow passage 13 is branched downstream of the pilot electromagnetic switching valve 14 and connected to the pilot chamber 26a. Therefore, when the pilot electromagnetic switching valve 14 is switched to the communication position, the first main switching valve 15 and the second main switching valve 26 are switched to thereby the first main pump 71 and the second main pump ( The hydraulic oil discharged from 72 is guided to the regenerative hydraulic motor 88.

The operation valves 2 to 6 are provided with a sensor 28 as a neutral position detector for electrically detecting the neutral position of the operation valves 2 to 6. The detection signal of the sensor 28 is output to the controller 90. The controller 90 determines whether all of the operation valves 2 to 6 are in the neutral position based on the detection signal from the sensor 28.

The sensor 28 corresponds to an operation state detector for detecting the operation state of the operation valves 2 to 6. The operation state detector of the present invention is not limited to the sensor 28 that electrically detects the neutral position of the operation valves 2 to 6, but is to hydraulically detect the neutral position of the operation valves 2 to 6. Also good. Specifically, the pilot passage which connects them in series to the operation valves 2 to 6 is provided, and when the operation valves 2 to 6 are switched from the neutral position to the switching position, the pilot passage is closed and the pilot passage is closed. A configuration in which the pressure changes is considered. In this case, the pressure in the pilot passage is converted into an electrical signal and output to the controller 90, and the controller 90 determines whether all the operation valves 2 to 6 are in the neutral position based on the electrical signal.

Moreover, as another structure which hydraulically detects the neutral position of the operation valves 2-6, you may provide the pressure gauge as a pressure detector which detects the pressure of the 1st pilot flow path 10a. The pressure signal detected by the pressure gauge is output to the controller 90. Since the pilot pressure of the 1st pilot flow path 10a changes with the operation amount of the operation valves 2-6, the controller 90 makes the operation valves 2-6 all the neutral positions based on the pressure signal which a pressure gauge detects. Can be determined. Specifically, in the controller 90, the pressure generated upstream of the throttle 9 when all the operation valves 2 to 6 are in the neutral position is stored in advance as the set pressure. When the pressure signal of the pressure gauge reaches the set pressure, the controller 90 determines that all the operation valves 2 to 6 are in the neutral position.

In the above description of the neutral position detector, the case of detecting the neutral position of the operation valves 2 to 6 has been described. However, the same applies to the operation valves 16 to 19.

The regenerative hydraulic motor 88 rotates in association with the generator 91. The hydraulic motor 88 is a variable displacement motor whose tilt angle is controlled by the regulator 30 connected to the controller 90. Power generated in the generator 91 is charged to the battery 29 through the inverter 92. The battery 29 is connected to the controller 90, and the controller 90 is able to grasp the amount of charge of the battery 29. The hydraulic motor 88 and the generator 91 may be directly connected or may be connected via a speed reducer.

The generator 1 installed in the engine 73 is connected to the battery charger 31, and the electric power generated by the generator 1 is charged in the battery 29 via the battery charger 31. The battery charger 31 is also connected to a power source 32 of another system such as a home power source.

An assist pump 89 is connected to the hydraulic motor 88. The assist pump 89 coaxially rotates with the hydraulic motor 88. The assist pump 89 is a variable displacement pump, the tilting angle of which is controlled by the regulator 33 connected to the controller 90. When the hydraulic motor 88 is exerting a power generation function, the assist pump 89 has its tilt angle set to the minimum in order to suppress the load acting on the hydraulic motor 88. On the other hand, when the generator 91 functions as an electric motor, the assist pump 89 rotates to exhibit a pump function.

The hydraulic oil discharged from the assist pump 89 is guided to the first main flow path 75 and the second main flow path 76 through the assist flow paths 34 and 35 provided in parallel. The flow path control valves 36 and 37 are provided in the assist flow paths 34 and 35, and allow only the flow of the hydraulic oil from the assist pump 89 to the first main flow path 75 and the second main flow path 76. Check valves 38 and 39 are provided.

The controller 90 determines that the actuators connected to the operation valves 2 to 6, 16 to 19 are in an operating state unless all the operation valves 2 to 6, 16 to 19 are maintained in the neutral position. Each valve is maintained in the normal state shown in FIG. 1 without exciting the solenoids of the first pilot selection valve 78, the second pilot selection valve 79, and the pilot electromagnetic switching valve 14. In this state, since the pilot pressure does not act on the pilot chambers 15a and 26a, the first main switching valve 15 and the second main switching valve 26 maintain the normal position shown in FIG. Therefore, the hydraulic oil discharged from the first main pump 71 is supplied to the first circuit system, and the hydraulic oil discharged from the second main pump 72 is supplied to the second circuit system.

In this state, the flow volume which flows through the neutral flow paths 7 and 20 changes according to the operation amount of the operation valves 2-6, 16-19. And the pilot pressure which arises in the upstream of the throttle parts 9 and 22 changes with the flow volume which flows through the neutral flow paths 7 and 20. As shown in FIG. According to this pilot pressure, the regulators 12 and 25 control the tilting angles of the first main pump 71 and the second main pump 72. Specifically, as the pilot pressure is lowered, the tilting angle is increased to increase the displacement per rotation of the first main pump 71 and the second main pump 72. On the contrary, the higher the pilot pressure, the smaller the tilting angle, so as to reduce the displacement per rotation of the first main pump 71 and the second main pump 72. Accordingly, the first main pump 71 and the second main pump 72 discharge the flow rate corresponding to the required flow rate according to the operation amount of the operation valves 2 to 6 and 16 to 19.

In addition, when the regulator 33 of the assist pump 89 is controlled to discharge hydraulic oil from the assist pump 89, the discharge oil is discharged from the first main pump 71 and the second main pump 72. Joined and supplied to the first and second circuit system. The assist pump 89 rotates by operating the generator 91 as an electric motor, and can use the electric power charged in the battery 29 to drive the assist pump 89. Moreover, the output torque of the hydraulic motor 88 can also be used as a drive source which rotates the assist pump 89. FIG.

Next, the control procedure executed by the controller 90 will be described with reference to FIGS. 2A and 2B. The controller 90 temporarily stores a CPU controlling the processing operation of the entire control device, a ROM storing programs, data, etc. required for the processing operation of the CPU, data read from the ROM, data read by each instrument, and the like. RAM and the like are stored.

In step 1, the detection signal detected by the sensor 28 provided in the operation valves 2-6, 16-19 is read.

In step 2, based on the detection signal of the sensor 28, it is determined whether all the operation valves 2-6, 16-19 are in a neutral position. In step 2, when it is determined that any one of the operation valves 2 to 6, 16 to 19 is in a switch position other than the neutral position, it is determined that the actuator connected to the operation valve is in operation, and the flow proceeds to step 3 Normal control is continued and the process returns to Step 1.

In step 2, when it is determined that all the operation valves 2 to 6 and 16 to 19 are in the neutral position, it is determined that each actuator is in the non-working state, and the flow advances to step 4.

In order to charge the battery 29 by rotating the hydraulic motor 88, it is required that there is a power generation request from the operator. The power generation request from the operator is made by the operator operating the switch for power generation request, and the standby regeneration command signal is input to the controller 90 by operating the switch. Therefore, in step 4, it is determined whether there is an input of a standby regeneration command signal. In step 4, when it is determined that there is no input of the standby regeneration command signal, the process returns to step 1.

In step 4, when it is determined that there is an input of the standby regeneration command signal, the process proceeds to step 5. In step 5, it is determined whether or not the battery 29 is near full charge.

If it is determined in step 5 that the charge amount of the battery 29 is in the vicinity of full charge, the process proceeds to step 6 and step 7. In steps 6 and 7, the solenoids of the first pilot selection valve 78 and the second pilot selection valve 79 are held non-excited, while the solenoids of the pilot electromagnetic switching valve 14 are held non-excited. As a result, these valves are held in the normal position shown in FIG. 1, and the flow returns to Step 1. When all of the first pilot selection valve 78, the second pilot selection valve 79, and the pilot electromagnetic switching valve 14 are maintained in the normal position, the discharge of the first main pump 71 and the second main pump 72 is performed. The oil flows from the first main switching valve 15 and the second main switching valve 26 via the neutral flow passages 7 and 20 and the first pilot flow passages 10a and 10b to form the first pilot selection valve 78. And from the second pilot selector valve 79 to the regulators 12, 25. The regulators 12 and 25 control the tilting angles of the first main pump 71 and the second main pump 72 by the pilot pressure generated upstream of the throttle parts 9 and 22. As a result, the discharge oil of the first main pump 71 and the second main pump 72 is maintained at the standby flow rate, and the standby flow rate is returned to the tank 94 via the throttle parts 9 and 22.

In step 5, when it is determined that the charge amount of the battery 29 is not near full charge, that is, the charge amount is insufficient, the process proceeds to step 8. In step 8, the solenoid of the pilot electromagnetic switching valve 14 is excited, and the pilot electromagnetic switching valve 14 is switched from the cutoff position of the normal position to the communication position. Thereby, pilot pressure oil is supplied from the pilot pump 96 to the pilot chambers 15a and 26a of the 1st main switching valve 15 and the 2nd main switching valve 26, and the 1st main switching valve 15 and The second main switching valve 26 is switched from the first position of the normal position to the second position. As a result, the hydraulic oil discharged from the first main pump 71 and the second main pump 72 is guided to the hydraulic motor 88.

In step 9, the solenoids of the first pilot selection valve 78 and the second pilot selection valve 79 are excited, and the first pilot selection valve 78 and the second pilot selection valve 79 are the first in the normal position. The position is switched from the position to the second position. As a result, communication between the first pilot flow passages 10a and 10b and the regulators 12 and 25 is interrupted, and the second pilot flow passage 11 and the regulators 12 and 25 communicate with each other. The regulators 12 and 25 control the tilting angles of the first main pump 71 and the second main pump 72 based on the pilot pressure derived from the second pilot flow passage 11.

In step 10, it is determined whether the rotation speed of the engine 73 detected by the rotation speed sensor 74 is low speed or high speed. Specifically, when the rotation speed detected by the rotation speed sensor 74 is equal to or less than the predetermined set rotation speed, it is determined to be low speed, and when it exceeds the set rotation speed, it is determined to be high speed. The set rotation speed is stored in advance in the ROM of the controller 90.

If it is determined in step 10 that the rotation speed of the engine 73 is high speed, the process proceeds to step 11. In step 11, the electromagnetic variable pressure reducing valve 77 is controlled to set the secondary pressure so that the displacement per rotation of the first main pump 71 and the second main pump 72 is in the vicinity of the minimum. Thus, when the rotation speed of the engine 73 is high speed, the exhaust volume per rotation of a pump was set to the minimum vicinity, The exhaust volume per rotation of a pump is at least 1st main pump 71 and the 2nd main pump 72. This is because the discharge flow rate per unit time of can be ensured. After step 11, the process proceeds to step 16, which will be described later.

If it is determined in step 10 that the rotation speed of the engine 73 is low, the flow advances to step 12 to determine the somewhat of the amount of charge of the battery 29. Specifically, it is determined whether the charge amount of the battery 29 is equal to or greater than a predetermined reference charge amount. The reference charge amount is stored in advance in the ROM of the controller 90.

If it is determined in step 12 that the charge amount of the battery 29 is equal to or greater than the reference charge amount, the flow proceeds to step 13. In step 13, the required charge amount is calculated based on the charge amount of the phenomenon of the battery 29, and the pump discharge flow rate according to the required charge amount is determined. On the other hand, if it is determined in step 12 that the charge amount of the battery 29 is less than the reference charge amount, the flow proceeds to step 14. In Step 14 as well, similarly to Step 13, the required charge amount is calculated based on the charge amount of the phenomenon of the battery 29, and the pump discharge flow rate according to the required charge amount is determined. Here, the pump discharge flow rate determined in step 13 is relatively smaller than the pump discharge flow rate determined in step 14.

After the pump discharge flow rate is determined in steps 13 and 14, the process proceeds to step 15. In step 15, the secondary pressure of the electromagnetic variable pressure reducing valve 77 is controlled by adjusting the excitation current applied to the solenoid of the electromagnetic variable pressure reducing valve 77. Thereby, the secondary pressure of the controlled electromagnetic variable pressure reducing valve 77 acts on the regulators 12 and 25, and the discharge flow volume of the 1st main pump 71 and the 2nd main pump 72 is 13 and 14, respectively. The tilt angle is set to be the pump discharge flow rate determined at. In this way, the first main pump 71 and the second main pump 72 discharge the flow rate required to charge the battery 29 with the required charge amount calculated in steps 13 and 14.

As described above, the secondary pressure of the electromagnetic variable pressure reducing valve 77 is controlled, and the discharge flow rates of the first main pump 71 and the second main pump 72 are controlled. And the hydraulic motor 88 rotates according to the discharge flow volume, and electric power generation is performed by the generator 91. The electric power generated by the generator 91 is charged to the battery 29 through the inverter 92. Thus, the regeneration by the standby flow volume discharged from the 1st main pump 71 and the 2nd main pump 72 is performed (step 16).

In addition, in the above description, when all the operation valves 2-6, 16-19 of the 1st and 2nd circuit system are hold | maintained in the neutral position, it demonstrated that regeneration by a standby flow volume is performed. However, the hydraulic motor 88 is rotated even when either one of the first and second circuit systems, that is, when the operation valves 2 to 6 are all in the neutral position, or when the operation valves 16 to 19 are all in the neutral position. Regeneration by the standby flow rate is performed. That is, when the discharge oil of any one of the 1st main pump 71 and the 2nd main pump 72 is supplied to the hydraulic motor 88, the hydraulic motor 88 will rotate and electric power generation will be performed by the generator 91. FIG.

According to the above embodiment, the effect shown below is exhibited.

When it is determined that all the operation valves 2 to 6, 16 to 19 are in the neutral position, the discharge oil of the first main pump 71 and the second main pump 72 is led to the regenerative hydraulic motor 88. Therefore, the standby flow rates of the first main pump 71 and the second main pump 72 can be effectively used.

In addition, since the pressure acting on the regulators 12 and 25 is variably controlled by the electromagnetic variable pressure reducing valve 77, the tilting angles of the first main pump 71 and the second main pump 72 are freely controlled as necessary. can do. Thus, there is no tendency for the energy for charging the battery 29 to run short.

In addition, when the rotation speed of the engine 73 is low, the 1st main pump 71 and the 2nd main pump 72 are controlled so that the exhaust volume per rotation may increase, and pump efficiency improves and it suppresses energy loss. can do.

In addition, since the tilting angles of the first main pump 71 and the second main pump 72 can be freely controlled, the engine for increasing the discharge flow rates of the first main pump 71 and the second main pump 72 is increased. It is not necessary to increase the rotation speed of 73, and energy loss can be suppressed.

In addition, since the 1st main pump 71, the 2nd main pump 72, and the hydraulic motor 88 are directly connected through the 1st main switching valve 15 and the 2nd main switching valve 26, it is 1st. There is no need to install a special valve between the main pump 71 and the second main pump 72 and the hydraulic motor 88. Therefore, the circuit configuration can be simplified.

In addition, in the said embodiment, the 1st main switching valve 15 and the 2nd main switching valve 26 are made into the 1st position and the 1st position based on the pilot pressure guide | induced to the pilot chamber 15a and the pilot chamber 26a. The pilot operated valve is switched to the 2 position. However, you may comprise the 1st main switching valve 15 and the 2nd main switching valve 26 with the electromagnetic valve switched to a 1st position and a 2nd position based on the output signal of the controller 90. FIG. In that case, the 3rd pilot flow path 13 and the pilot electromagnetic switching valve 14 become unnecessary.

This invention is not limited to the above-mentioned embodiment, It is clear that various deformation | transformation and a change are possible in the range of the technical idea, and they are also included in the technical scope of this invention.

Regarding the above description, the content of Japanese Patent Application No. 2009-164278 in Japan having July 10, 2009 as an application date is incorporated herein by reference.

Industrial Applicability The present invention can be used for control devices of construction machinery such as power shovels.

Claims (5)

It is a control unit of the hybrid construction machine,
Variable displacement pumps,
A plurality of operation valves for controlling a flow rate of hydraulic oil guided from the variable displacement pump to each actuator;
A neutral flow path for guiding discharge oil of the variable displacement pump to a tank when the operation valve is in a neutral position;
A pilot pressure generating throttle portion provided downstream of the operation valve in the neutral flow path;
A first pilot flow path for inducing pressure generated upstream of the pilot pressure generating throttle;
A regulator for controlling the tilting angle of the variable displacement pump to increase as the pilot pressure acting lower;
An operation status detector for detecting an operation status of the operation valve;
A regenerative hydraulic motor rotating by the discharge oil of the variable displacement pump;
A generator connected to the hydraulic motor,
A main switching valve for selectively inducing hydraulic oil discharged from the variable displacement pump to the operation valve or the hydraulic motor;
A second pilot flow path for guiding pilot pressure oil supplied from a pilot pressure source to the regulator;
A pilot selection valve for selectively communicating the first pilot flow passage or the second pilot flow passage with the regulator;
An electromagnetic variable pressure reducing valve installed in the second pilot flow path and capable of variably controlling a pilot pressure induced from the pilot pressure source and acting on the regulator;
On the basis of the detection result of the operation state detector, when it is determined that all of the operation valves are in the neutral position, the main switching valve is switched so that the discharge oil of the variable displacement pump is guided to the hydraulic motor, and the second And a controller for switching the pilot selector valve so that a pilot flow passage communicates with the regulator. The said main switching valve is a pilot operated valve | bulb switched by the pilot pressure oil supplied from the said pilot pressure source,
A third pilot flow passage for guiding pilot pressure oil supplied from the pilot pressure source to a pilot chamber of the main switching valve;
A pilot electromagnetic switching valve installed in the third pilot flow path and switched to a cutoff position or a communication position based on an output signal of the controller,
When the controller determines that all of the operation valves are in the neutral position, the controller of the hybrid construction machine switches the main switching valve by setting the pilot electromagnetic switching valve to a communication position. The method of claim 1, wherein the electromagnetic variable pressure reducing valve, based on the output signal of the controller, the pilot pressure acting on the regulator to maintain the maximum tilt angle from the pressure to maintain the minimum tilt angle of the variable displacement pump. Control device for hybrid construction machines, capable of controlling up to pressure. The motor of claim 1, further comprising: a prime mover for driving the variable displacement pump;
It further comprises a rotation speed detector for detecting the rotation speed of the prime mover,
The controller judges that all of the operation valves are in a neutral position, and when the rotation speed detected by the rotation speed detector exceeds a predetermined set rotation speed, the controller controls the secondary pressure of the electromagnetic variable pressure reducing valve to the variable displacement type. The control apparatus of the hybrid construction machine which controls so that the displacement per rotation of a pump may be minimum. According to claim 1, further comprising a battery that is charged with the electric power generated by the rotation of the hydraulic motor,
When the controller determines that all of the operation valves are in the neutral position, the controller calculates a required charge amount based on the charge amount of the battery, determines the discharge flow rate of the variable displacement pump according to the calculated required charge amount, The control device of the hybrid construction machine, which controls the secondary pressure of the electromagnetic variable pressure reducing valve so that the discharge flow rate of the variable displacement pump becomes the determined discharge flow rate.

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